Wednesday, December 31, 2014

ShapeOko 2 Build: Part 1

I've been watching the ShapeOko2 from Inventables for the last year. I've been interested in DIY CNC for the last several years, but the time wasn't right to jump in. When their kit went on sale for "small business Saturday" I decided the time to order the kit had arrived. I decided to spring for "the works" kit which includes the Quiet Cut spindle and a bunch of other upgrades.

The kit was very complete, down to including all the tools you'd need for mechanical assembly, and well packed. The basic instructions on their website were also very good. However, I was a bit underwhelmed with the documentation included for the extras in "the works" kit. The inventables website did have a page: ShapeOko 2 "The Works" kit instructions- not really instructions, but has at least a few more details.

So far, I have the mechanical assembly complete, and have started to wire up the system. The first challenge was to attach the drag chains / cable chains included in the expanded kit. Mounting brackets were not included. The Shapeoko2 wiki did reference these 3D printable drag chain mounts, they look nice but they don't fit the drag chains included in the shapeoko2 "the works" kit. I ended up designing a set of brackets (files posted here on thingiverse) since I couldn't find any ones on Thingiverse that seemed to do what I'd like.

A few of the brackets I designed, ready for trial mounting. (these were old versions, I ended up not using them)

X-axis carriage with drag chain mount. Wires not yet routed through chain

Outboard X-axis drag chain mount installed, again wires not yet routed through chain

It's getting closer to running....

As soon as I have the steppers all wired I'll start in on the Quiet Cut spindle. There are a few different sets of installation instructions- I have yet to choose one to follow:

Quiet Cut Spindle installation instructions:

Quiet Cut Spindle w/TinyG electronics instructions:

Tuesday, December 2, 2014

45Nrth Vanhelga tubeless setup with Marge Lites

It was time for some new, more aggressive tires for the fatbike. The Husker Du's I have are great on dirt and hard pack snow, but in looser conditions they really struggle. I'm planning on putting them back on next spring. 

45Nrth has a new tubeless ready tire called the Vanhelga that has been getting great reviews- I decided to give it a try. It seems to be the widest, most aggressive tire I can fit in my old school 170mm 9:zero:7. New snowbike tires are not for the faint of heart-  they certainly lighten the wallet. I've never paid this much per tire for even car tires!

Apply for a loan before you bring these to the counter
I decided to go with the more expensive 120TPI version- even with the additional cost, it's probably the cheapest way to knock some serious weight off of a fatbike.

As soon as I got home I tossed the tires on the scale:

120TPI 45Nrth Vanhelga: 1279g & 1298g each

Amazing that this aggressive of a tire is as light as it is.

Motorcross or Snowbike Tire?

"old" tires: 45Nrth Husker Du, 60TPI
As I took parts off the bike in preparation for changing out the tires (and attempting a tubeless conversion) I put everything on the gram scale.

Old Front Wheel setup: 3380g (all up inc. tire, tube, etc)

Bare Front Wheel: 1345g

  • MargeLite rim
  • 907 135mm hub
  • 160mm rotor
  • spokes, etc

Surly rimstrip: 60g
Bontrager 26x2.50-2.80 Tube: 280g

45Nrth Husker Du, 60TPI: 1650g

I'm going to attempt a tubeless conversion, but not the full "ghetto" tubeless conversion with split inner tubes, sill foam, etc. I'm going to first just try a solid rim tape setup and go from there.

Supplies, ready to go


  • 3M 8898 Tape, 72mm width
  • Reflective Tape, cut down to ~43mm width
  • Stan's valve stems
  • Stan's sealant
  • Tires

1) remove tire, tube & rimstrip
2) true wheel
3) clean rim with rubbing alcohol
4) Cut down reflective tape & wrap around rim, securing at one end with small piece of tape, then stick to itself
5) apply 3M 8898, try to keep centered
6) carefully stick tape down to bead seat area of rim

Tire & rim strip removed, rim cleaned, truing it up. 
Starting to wrap inner layer of reflective tape- sticky side "out", reflective side in (to show through rim cut-outs)
Full wrap of reflective tape
Getting the 72mm wide 3M 8898 wrapped down tightly was tough- it's nice and tight over bead seat area but not in the center.

1384g after reflective rim strip & 72mm 3M 8898

That's one beefy tread pattern
It looked good and I had high hopes for an easy tubeless setup, but no luck. I couldn't get the bead to seat even using the tie down strap method, with valve core removed and an air compressor. I tried putting a tube in, seating the beads, popping one bead, removing the tube, and trying again- but no luck. There is just too much room between the tire bead and the center of the rim. I think it'd work fine using the sill foam tape trick, but that'll be for another day.

So, I gave up tubeless for now- re-installed tube. Even with a tube there was substantial weight savings from the new tire:
2920g Front wheel, new rim strips, tube & new tire = 460g savings from the front wheel alone

I repeated the process with the rear tire, minus the tubeless attempt.

Old Rear Tire on wheel: 3920g (all up, tire, tube, etc)

Bare rear wheel: 1897g (no rimstrip)

  • MargeLite
  • 907 170mm hub
  • 160mm rotor
  • Cassette w/ 42T Giant Cog
  • spokes, etc
Bare rear wheel with 72mm 3M 8898 & reflective tape: 1962g
rear wheel with Vanhelga, Tube: 3470g = 450g savings

So, just changing out tires and rim strips to the new 120TPI Vanhelga's yields 910g weight savings, just a hair over 2 pounds. Pretty amazing, especially considering the new tires are both wider and have much, much more aggressive tread patterns.

Still plenty of chain clearance with a 1x10 setup. A 2x10 might be pretty tight. 

A short ride around a frozen lake with 2-4" of snow shows the new tires function much better in loose snow- they tracked and gripped with authority. I'm hoping to ride some snow-covered singletrack this weekend!

I'm also going to search through Menard's and try to find some self adhesive foam tape for the tubeless conversion.

Sunday, November 23, 2014

Canoe seat replacement using woven polypro webbing

Our old wicker canoe seats were in terrible shape by the end of this summer. I was inspired by some nice woven seats I saw at the Minnesota State Fair, I decided to try replacing the original wicker / cane seats with something similar using a synthetic webbing.

reference canoe seat at the Fair

bottom of the reference canoe seat at the Fair
A quick search on brought up a bunch of choices for webbing- different materials, colors, and sizes. I did some research online, and it seemed as though Polypropylene webbing is a better choice than nylon webbing. The polypro webbing is supposed to be more weather / UV resistant, as well as less stretching when they get wet. I decided to go with 1" wide webbing since it would also be useful for belts, backpack straps, etc. I purchased a roll of the Country Brook Design 1" polypro black webbing via

To fasten the webbing to the seat frame, I chose to use a staple gun and 1/2" x 1/4" crown 18 ga staples. These were the shortest staples I could find that would fit my Porter Cable pneumatic staple gun. Lowe's and Home Depot didn't have small boxes of this size staple- they only carried 3000+ staple cases.  Menards turned out to carry a reasonable size box of staples.

 After stripping the old woven cane seat off the canoe seat frames, I started cutting the webbing to length. I wanted a tight weave, so I laid out the webbing on the seat frame with no gaps between pieces. I cut the webbing with a heavy duty kitchen scissors and sealed the cut ends with a lighter to prevent fraying.

Starting webbing layout

 I started attaching the webbing by stapling the end strand to the frame.

End webbing attached
 Next, I lined up and stapled the webbing to the "side" and "bottom" of the frame.

After one end of each of the webbing segments was attached, I flipped the seat over and started weaving the strands, working my way out from the corner where the segments were attached.

Starting to weave the strands
 During the weaving process, I'd stop occasionally and pull everything tight.

Nearly complete
After all segments were woven, and after I pulled out as much slack as possible, I started to staple down the loose ends. Before stapling each segment I'd grab the segment and pull it as tight as I could, and I also would slide it over to get it as close as possible to the adjacent segment.

Bottom stapled

Everything stapled!

Bottom of seat after stapling

Both seats, ready to go

Installed- ready for paddling!
This project was a lot easier and faster than I thought- and made the canoe seats much more comfortable.

Friday, June 27, 2014 Carbon Wheels Initial Review

The Light-Bicycle carbon hoops showed up about a month after ordering. They were packed really well in a surprisingly small box. They seemed to be very true and round, and spoke tension seemed even. 

The box was a little beat up....

But the wheels seemed well protected.

I chose the new 29" "hookless" style rim, standard black bladed spokes, blue alloy nipples, and Hope Evo2 hubs. Customer service was great, they responded very quickly to e-mails. Make sure to send them a message and clarify exactly which rim you want- they seem to have once set of choices for rim only, and one set for pre-built wheels.

Check the hookless profile

Weights: (bare wheels, w/o tape)
686g front
813g rear

I applied Stan's tape, Stan's valve stem & sealant, and they seated just fine with a set of Maxis Ikon tires- using a floor pump. So far so good, although they've only been off road once because of all the wet weather. 

Qualitatively they seem zippier and easier to accelerate.... I have yet to ride anything technical on them and I'm curious how they feel in rock gardens and hard corners. 

New bling!

Mounted and ready to ride!

Sunday, June 22, 2014

MakerBot Replicator 2x: More Air Prints, custom heat sink

I am increasingly frustrated with the MakerBot Replicator 2x we have at the office. It seems you need to spend twice the amount of time working on it as you get viable prints. After a streak of good luck and reliability, as of late it refuses to complete any kind of medium or large size print job. It'll get part of the way complete, and then stop feeding filament- a classic air print.

I am guessing the problem is because the aluminum block that holds the stainless steel feed throat for the hot ends in place isn't cooled sufficiently. If it gets too warm, the stainless steel feed throat will get too warm, and the filament will soften before it gets to the hot end nozzle and jam. I thought I would attack this problem by creating an improved heat sink and attempt to move more heat away from the aluminum block, and thus attempt to keep the stainless steel feed throat cooler. I also attempted to improve the insulation between the hot ends and the aluminum block.

First, I constructed a heat sink using 1/8" thick copper sheet purchased from Mcmastercarr. I thought the copper would create a improved heat flow path from the aluminum block to both of the fan-cooled heat sinks, as well as increase the total mass of the heat sink. It should also allow improved heat flow from the aluminum block near extruder #1 to extruder #2's heat sink.

Heat sink cut, drilled, and ready to go

Trial fit of stock heat sinks checking for hole alignment

Test fit on drive block

Test fit on drive block
 Next, I wanted to reduce the convective & radiant heat transfer from the hot ends to the drive block by adding some 1/32" thick silicone rubber, also sourced from

Covering all air gaps on the top of the extruder platform

Sheet of self-adhesive rubber cut to fit the bottom of the aluminum hot end block

Adhered to the bottom of the aluminum block

Extruder #2 Re-attached
During this assembly and dissemble, the thermistor / thermocouple for hot end #1 failed. The stock cables are very thin and fragile, so it wasn't much of a surprise. Makerbot actually sent a replacement thermocouple free of charge. The new thermocouple wire is much thicker and appears more durable than the stock cable.

New Makerbot Replicator 2x thermocouple on the left, original on the right. The stock cable used much smaller gage cable. 
Since this is not the first time I've completely disassembled extruder #1's hot end, the stock ceramic / polyimide / insulation hot end insulation was cracked and looking pretty sad. Rather than tape it back together with some kapton tape I ordered a replacement insulation set off of from VIRA design.

Mini-Review of the Vira Design Makerbot Replicator 2x upgrade kit, AKA: Upgrade Kit for the Hot End Insulation on Makerbot Replicator 2x-extruder-reprap

  • Shipping: Slow-  took about two weeks- it appears as though they paid for shipping, then make the parts, then shipped them out. 
  • Packaging: Poor- all the parts were tossed in a much-too large box- although since nothing it breakable it didn't matter
  • Instructions: Poor- zero instructions included with the kit, although if you are capable of installing it you'll be able to figure it out
  • Part quality: Good- cast silicone parts are serviceable, but required x-acto knife cleanup of all thru-holes
  • Value: Good - you'll have a hard time producing these parts yourself for much less, let alone the time required to design, create molds, and make the parts. If you need replacement insulation for your hot ends these are a good option. Plus they are completely non-fragile, unlike the stock ceramic insulation. 
Vira Design upgrade kit for Hot End Insulation on Makerbot Replicator 2x Mini-instructions:

1) Use an X-acto knife to clean out all of the thru-holes in the silicone insulation parts.
New rubber insulation on the right., prior to trim
 2) Cut the white insulation to size for the flat end of the aluminum hot end block.

Using aluminum hot end block as pattern to cut white insulation
 3) Cut kapton / polyimide tape to hold the white insulation to the aluminum block
Cut tape using X-acto
 4) Stick white insulation patch to kapton tape
Ready to go
 5) Attach insulation patch to aluminum hot-end block
Attach tape / insulation patch to aluminum hot end block

Insulation in place
 6) Insert hot-end assembly into silicone insulation
Ready to go!
 Next up, loading new thermocouple into hot end block. I put a dab of thermal heat sink compound onto the threads to improve heat conduction and also to prevent the thermocouple threads from seizing in the aluminum block. When I threaded it in I rotated the aluminum block rather than the thermocouple to minimize any stress on the thermocouple wire. I also only tightened it finger tight- no tools used.

Thermal heat sink compound on thermocouple threads

Hot End #1 installed. 
Next up, finish installation and fire it up.

Thermal compound on the interface between the new copper heat sink and the aluminum hot end block

Thermal compound on the back of the aluminum fan cooled heat sinks

Up and running!

So, after all this, you'd expect it runs perfectly..... And the answer is... NO! Very frustrating. It might work slightly better but I'm still getting air prints. So far I've only been trying authentic MakerBot brand natural ABS filament. I'll try using some generic colored ABS filament- I believe it has a higher melt temp, which might help.